Universal hinged treads for folding attic stairs

ABSTRACT

A universal hinged tread system includes a folding stair set with one or more primary treads. At least one auxiliary tread is hingedly attached atop at least one primary tread. The folding stair set includes at least two hingedly attached sections. The hingedly attached sections fold flat against each other when in a stowed position, and every other folding stair section is inverted when in the stowed position. Each auxiliary tread is angularly displaced from its primary tread as its folding stair section is inverted. The auxiliary treads do not obstruct any primary treads on other sections when in a stowed position. The auxiliary treads include a beveled lower front edge to aid the auxiliary treads in deflecting.

PRIORITY DATA

This application is a claims priority from U.S. Patent Applicationserial No. 60/622,961 filed on Oct. 28, 2004, entitled “Universal HingedTreads for Folding Attic Stairs” and is hereby incorporated byreference.

FIELD OF THE INVENTION

This invention relates generally to the field of ladders and stairs, andmore specifically to an auxiliary tread system for ladders and stairs.

BACKGROUND OF THE INVENTION

In many homes and businesses, pull-down attic stairs are a necessaryevil. Typical applications for these stairs are where additional storagespace is required, but nothing is available in the structure except foran attic crawl space.

If an attic crawl space is all that is available, then the occupantswill need to determine a quick, cheap and reliable means of accessingthe attic. A portable utility ladder is one solution, however, portableutility ladders are too portable. They are not very stable at times, andrequire a spotter for safety. In addition, ladders are easily taken awayand used for other purposes, which effectively prevents access to theattic.

One solution to this problem is a set of pull-down attic stairs. Thesestairs are permanently attached to a ceiling panel and mounted betweenceiling studs. One end of the panel is attached to the ceiling with ahinge, and the other end of the panel can be pulled down away from theceiling. The unhinged end is biased up toward the ceiling with a largespring mechanism. After the panel is pulled down, a set of stairs isunfolded down to the floor. This device is an easy way to have apermanent, easily accessible set of stairs available, but these stairshave several shortcomings.

The first shortcoming is that the individual treads are quite shallow,when measured from front to back. Shallow treads do not inspireconfidence when ascending and descending; only a very limited amount ofthe user's foot is in contact with each tread. Manufacturers do not makethe treads any deeper because deeper treads will extend beyond the frameand interfere with the treads on other sections of the folding stairs.For these manufacturers, in order to enable the treads to be deeper, theframe must be made larger. This is not a good solution wheremanufacturers are trying to control material costs, and the largerstairs may not fit into the available ceiling space.

For those whose existing stairs have these shortcomings, the solutionsare either to replace the entire folding stair set, or to add deepertreads to the existing stair set. Replacing the entire stair set can bequite expensive and time-consuming.

Thus, what is desired is a set of deep treads that are easily attachedto an existing stair set. The treads should be large enough to inspireconfidence when ascending and descending, but should not interfere inany way with the function of the stair set.

It is intended that any other advantages and objects of the presentinvention that become apparent or obvious from the detailed descriptionor illustrations contained herein are within the scope of the presentinvention.

SUMMARY OF THE INVENTION

The device is a universal hinged tread system that has auxiliary treadsfor attachment to the primary treads on an existing stair set. Eachauxiliary tread includes a hinge pin that is incorporated into theauxiliary tread. The auxiliary tread and its hinge pin can be formed asan integral unit from a high-strength plastic. A hinge plate is fastenedto the primary tread and traps the hinge pin against the primary tread.Where the deployed auxiliary tread bears against the hinge plate, theauxiliary tread is relieved to compensate for the thickness of the hingeplate. Thus, the auxiliary tread bears evenly against the hinge plateand the primary tread. The auxiliary tread is deeper, measured fromfront to back, than the original primary tread. The auxiliary tread andthe hinge plate are approximately even with the back side of the primarytread. The extra depth of the auxiliary tread hangs over and extendsfrom the front of the primary tread. This provides are greater surfacearea for the user and inspires greater confidence in ascending anddescending the stairs.

The following is a discussion and description of the preferred specificembodiments of this invention, such being made with reference to thedrawings, wherein the same reference numerals are used to indicate thesame or similar parts and/or structure. It should be noted that suchdiscussion and description is not meant to unduly limit the scope of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a perspective view of a universal hinged tread system, withthe auxiliary treads attached to the primary treads, according to thepresent invention;

FIG. 2. is a side view of the universal hinged tread system, partiallyfolded, according to the present invention;

FIG. 3 is a side view of the universal hinged tread system, almostcompletely folded, according to the present invention; and

FIG. 4 is a side view of the universal hinged tread system, partiallyextended, according to the present invention.

The following is a discussion and description of the preferred specificembodiments of this invention, such being made with reference to thedrawings, wherein the same reference numerals are used to indicate thesame or similar parts and/or structure. It should be noted that suchdiscussion and description is not meant to unduly limit the scope of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best presently contemplatedmodes of carrying out the invention. This description is not to be takenin a limiting sense, but is made merely for the purpose of illustratinggeneral principles of embodiments of the invention.

Referring now to the drawings, the attached figures illustrate a systemhaving universal hinged treads for folding attic stairs.

FIG. 1. is a perspective view of a universal hinged tread system, withthe auxiliary treads 10 attached to the primary treads 12. Eachauxiliary tread 10 includes a hinge pin 16 that is incorporated into theauxiliary tread 10. The auxiliary tread 10 and its hinge pin 16 can beformed as an integral unit from a high-strength plastic. Alternatively,the auxiliary treads 10 may be made from lumber, such as plywood, anddoor hinges or other common equivalents. A hinge plate 14 is fastened tothe primary tread 12 and traps the hinge pin 16 against the primarytread 12. Where the deployed auxiliary tread 10 bears against the hingeplate 14, the auxiliary tread 10 is relieved to compensate for thethickness of the hinge plate 14. Thus, the auxiliary tread 10 bearsevenly against the hinge plate 14 and the primary tread 12. Theauxiliary tread 10 is deeper, measured front to back, than the primarytread 12. The auxiliary tread 10 and the hinge plate 14 areapproximately even with the back side of the primary tread 12. The extradepth of the auxiliary tread 10 hangs over and extends from the front ofthe primary tread 12. This provides are greater surface area for theuser and inspires greater confidence in ascending and descending thestairs.

FIG. 2. is a side view of the universal hinged tread system, where thestairs are partially folded. Each of the primary treads 12 has anauxiliary tread 10 attached via a hinge. The folding stair set shownincludes three hingedly attached sections. The upper section A attachesinto a ceiling or similar support at it upper end. The center section Bis attached via a hinge D to the bottom of the upper section A. Thelower section C is attached via hinge E to the bottom of the centersection B. The hinges D,E between these sections A,B,C are arranged sothat they fold flat against each other when in a stowed position. AsFIG. 2 shows, every other folding stair section is inverted when in thestowed position. In this case, section B is inverted as the stairs arestowed. As section B is inverted, each auxiliary tread 10 is angularlydisplaced from its primary tread 12. This displacement occurs due togravity. No springs, biasing means or power is required. The auxiliarytreads 10 are displace from a deployed position ∀ to a stowed position2. The auxiliary treads 10 do not obstruct any primary treads 12 when inthe stowed position 2. This is important because the auxiliary treads 10extend a significant distance beyond the primary treads 12 and theirstringers 18. If the auxiliary treads 10 did not move from theirdeployed position ∀, they could interfere with the primary treads 12 onsections A and C.

FIG. 3 is a side view of the universal hinged tread system, where thestairs are almost completely folded. In this view, section B is almostflat against section A. The auxiliary treads 10 on section B havedisplaced from ∀ to 2, due to gravity, and will not interfere with thetreads 10, 12 on section A. However, due to the layout of the primarytreads 12 on many folding stair sets, there is still a possibility ofinterference between the auxiliary treads 10 of an upright stairsection, such as section A, and the primary treads 12 on an invertedstair section, such as section B. In these cases, it is necessary forthe auxiliary treads 10 on section A to deflect slightly in response tocontact with the primary treads 12 on section B. FIG. 3 shows thisinteraction. Notice that the auxiliary treads 10 on section A aredeflected upward about 15 degrees in response to contact with theinverted primary treads 12 of section B. To enable this deflection, theauxiliary treads 10 include a beveled lower front edge. This bevel actsas a ramp or cam to lift or deflect the auxiliary tread 10 away from theinterference. The hinged auxiliary treads 10 on the upright stairsections, such as sections A and C, are most useful on folding stairsets where the primary treads 12 on adjoining sections A,B,C are closelyarranged or almost touching when stowed, such as shown in FIG. 4.

FIG. 4 is a side view of the universal hinged tread system, where thestairs are completely stowed. Notice that the primary treads 12 on eachof the adjoining sections are about even. This arrangement of primarytreads 12 creates the interference that necessitates the deflection ofthe auxiliary treads 10 on section A. The auxiliary treads 10 on sectionA are now laying flat against the primary treads 12 of both sections Aand B. Each of the auxiliary treads 10 on section B have been displacedand are now simply hanging from the hinges 16.

Redeployment of the folding stair set is simply the reverse operation.Sections C and B are unfolded from A. The auxiliary treads 10 of sectionA are briefly deflected as the section B is separated from section A.The stair sections, A,B,C are unfolded to their full extension, and assection B is extended, its auxiliary treads 10 automatically fall from 2to ∀, due to gravity. The automatic deployment of the auxiliary treadsoccurs when the angle between ∀ and 2 is less than 90 degrees.Alternatively, the stowed position 2 may include an angle, greater than90 degrees from ∀, that requires the user to move the auxiliary treads10 to position ∀.

In an alternative embodiment, a stair set may be made without the usualprimary treads 12. In this case, the stair set includes a frame with aset of stringers and a plurality of hinged auxiliary treads 10 mountedto the stringers. As above, each auxiliary tread 10 is deeper than thestringers. However, because there are no primary treads 12 to supportthe auxiliary treads 10, the hinge is attached directly to the stringersand provides the horizontal support for the auxiliary treads 10. Asanother embodiment, the auxiliary treads 10 may be used without hingesand primary treads 12. In this case, the deep auxiliary treads 10 areattached directly to the stringers without any hinges. Small brackets ocould be used to secure the treads 10 to the stringers, or a flangecould be incorporated into the treads 10. As shown in FIG. 4, theauxiliary treads 10 cannot simply be placed where the primary treads 12are. As the stair set is folded, the auxiliary treads 10 would contactand interfere. In order to avoid this issue, the auxiliary treads 10need to be shifted collectively a few inches up or down the stringers.In that manner the stair set would have large, evenly-spaced treads, andcould also be folded flat for storage.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

1. A universal hinged tread system comprising: a stair set furthercomprising one or more primary treads; at least one auxiliary treadhingedly attached atop at least one primary tread.
 2. The universalhinged tread system of claim 1, where the folding stair set comprises atleast two hingedly attached sections.
 3. The universal hinged treadsystem of claim 2, where the at least two hingedly attached sectionsfold flat against each other when in a stowed position.
 4. The universalhinged tread system of claim 3, where every other folding stair sectionis inverted when in the stowed position.
 5. The universal hinged treadsystem of claim 4, where each auxiliary tread is angularly displacedfrom its primary tread as its folding stair section is inverted.
 6. Theuniversal hinged tread system of claim 1, where the auxiliary treads donot obstruct any primary treads when in a stowed position.
 7. Theuniversal hinged tread system of claim 6, where the auxiliary treadscomprise a beveled lower front edge.
 8. A climbing and descending devicecomprising: a frame comprising a set of stringers; a plurality of treadshingedly mounted to the stringers, where each tread is deeper than thestringers, and where each tread deploys to a horizontal position.
 9. Theclimbing and descending device of claim 8, where the frame comprises anupper section, a center section and a lower section, where the uppersection is attached to the center section via at least one hinge, andthe lower section is attached to the center section via at least onehinge.
 10. The climbing and descending device of claim 9, where eachtread is limited to a position no lower than horizontal when the framesections are fully extended.
 11. The climbing and descending device ofclaim 10, where the center section is inverted as the frame sections arestowed.
 12. The climbing and descending device of claim 11, where thetreads of the center section move to a position of noninterference withthe upper section and the lower section as the frame sections arestowed.
 13. A method of stowing a folding stair set comprising the stepsof: (a) raising a hingedly attached folding stair section from adeployed position, where the folding stair section has a plurality ofprimary treads with hingedly attached auxiliary treads; (b) invertingthe folding stair section; (c) angularly displacing the plurality ofauxiliary treads from the plurality of primary treads; (d) moving thefolding stair section toward a stowed position; and (e) placing thefolding stair section into the stowed position.
 14. The method ofstowing a folding stair set of claim 13, where the folding stair sectionis a center section, and a lower section is hingedly attached to thecenter section.
 15. The method of stowing a folding stair set of claim14, where step (a) further comprises the step of: (a1) raising the lowersection from the deployed position.
 16. The method of stowing a foldingstair set of claim 15, where step (b) further comprises the step of:(b1)) inverting the center section.
 17. The method of stowing a foldingstair set of claim 16, where step (c) further comprises the step of:(c1) limiting the displacement of the auxiliary treads to about 110degrees.
 18. The method of stowing a folding stair set of claim 16,where step (c) further comprises the step of: (c1) limiting thedisplacement of the auxiliary treads to about 70 degrees.
 19. The methodof stowing a folding stair set of claim 16, where step (d) furthercomprises the step of: (d1) when the auxiliary treads on an uppersection contact the primary treads on the center section, deflecting theauxiliary treads on the upper section.
 20. The method of stowing afolding stair set of claim 19, where step (e) further comprises thesteps of: (e1) placing the center section flat against an upper section;and (e2) placing the lower section flat against the center section.